A typical bone plate such as described in WO 2004/089233 of Thielke, US 2006/0229619 of Orbay, US 2006/0235404, or US 2007/0055253 all of Orbay, extends along an axis and has an outer end that is fan-shaped and formed with an array of holes so that it can be solidly screwed to the epiphysis to one side of the fracture or other injury that is to be reduced so the bone can grow back together. Extending from this fan-shaped outer end is a flat narrow bar formed with another array of holes allowing it to be screwed to the bone's diaphysis. The most common use of such a bone plate is in setting or reducing a distal fracture of the radius, but it can of course also be used for any type of fracture on a distal portion of a long bone.
Because of the presence of tendons and ligaments, reducing such a break is difficult, especially considering that the more tightly the two bone parts can be engaged together the more quickly arthrodesis will mend the fracture.
The problem with such a plate is that it allows little or no adjustment once secured in place. The system of US 2007/0233114 of Bouman has transverse and longitudinal slots allowing some longitudinal and transverse shifting of parts, but in a structure intended for use on a bone shaft. It is known to form the inner bar-shaped part of the plate with an axially extending slot to allow the epiphysis and the bone plate to be shifted limitedly longitudinally of the bone to close up a fracture. Thus the orthopedic surgeon fixes the plate on the distal fragment, installs a screw loosely in the slot and pushes the distal fragment back into contact with the proximal portion of the bone, thereby making the screw slide in the hole up to the point where the two bone parts come in direct abutment with one another. In this position of the plate, the screw extending loosely through the longitudinal slot is tightened to lock in the set position.
The surgeon therefore cannot correct a transverse positioning defect, except if he redrills the proximal fragment near the first hole at an offset. In practice, this is often impossible since the two holes would be too close to one another. Therefore the transverse defect is normally left uncorrected so that the outer end of the plate overextends on the side, which can be unattractive and can cause patient discomfort.